In my experience, they're generally more complicated. The reason is that a firearm doesn't do any of the work of propelling the projectile--it's all done by the stored energy in the gunpowder. An airgun has to provide the means to store and/or generate energy to actually do the work of propelling the projectile and that means added mechanisms and more complexity.

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Also, pneumatics, precharged or pump up have a hard time matching the power of a springer.

True, with the exception of the precharged pneumatics which can easily match or exceed the power of a springer. Since they can store a tremendous amount of energy in the form of a considerable volume of compressed air, they can rival the power of black-powder firearms with large, heavy projectiles while even the most powerful springers tend to top out at around 35ft/lbs.